Switching video streams for a display without a visible interruption

Abstract

The disclosed embodiments provide a system that facilitates driving a display in a computer system. During operation, the system receives an input video stream from a graphics source. The system directs the input video stream through a front memory buffer and a back memory buffer to produce an output video stream. While directing the input video stream through the set of memory buffers, the system writes a video frame from the input video stream into the back buffer, and concurrently drives the output video stream from a preceding video frame in the front buffer. When the writing of the video frame completes, the system switches buffers so that the back buffer becomes the front buffer, which drives the output video stream, and the front buffer becomes either a spare buffer or the back buffer, which receives a subsequent frame from the input video stream.

Description

BACKGROUND[0001]1. Field[0002]The disclosed embodiments relate to techniques for switching between graphics sources to drive a display in a computer system. More specifically, the disclosed embodiments relate to a buffering technique that facilitates switching between graphics sources to drive a display without a visible interruption.[0003]2. Related Art[0004]To operate without interruption, computer displays require a constant video stream from a graphics source. However, a modern computer systems often drives a display from different graphics sources. For example, a computer system may include multiple graphics processing units (GPUs), which provide differing levels of graphics-processing performance and consume different amounts of power. This enables the computer system to switch a display between different GPUs in a manner that balances changing graphics-processing requirements and power consumption. Unfortunately, video streams from the different graphics sources are not neces...

AI Technical Summary

Benefits of technology

[0009]In some embodiments, after the switching operation completes, if the switching operation introduced a buffering time lag between the input video stream and the output video stream, the system reduces the time lag during successive video frames until the time lag is eliminated.

[0011]In some embodiments, the system switches the input video stream to a live path, which bypasses the set of memory buffers, to produce the output video stream. After the input video stream is switched to the live path, the system can conserve power by removing power from the set of memory buffers.

Problems solved by technology

For example, a computer system may include multiple graphics processing units (GPUs), which provide differing levels of graphics-processing performance and consume different amounts of power.

Unfortunately, video streams from the different graphics sources are not necessarily synchronized with each other, and the process of starting up a graphics source can take some time.

As a consequence, the process of switching between different graphics sources can cause user-visible display glitches.

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